1. Field of the Invention
The present invention generally pertains to marine and recreational vehicle (RV) waste holding tanks and, more particularly, odor reduction systems for such waste holding tanks.
2. Description of Related Art
The direct overboard discharge of untreated sewage from toilets aboard marine vessels has been prohibited by law for many years. Waste from toilets is generally flushed by the toilet system into a holding tank where it is held for treatment, or for disposal into a land-based sewage handling system. For safety reasons, the holding tank is always vented to atmosphere. As a result, each time additional sewage is flushed into the holding tank, air within the holding tank is displaced by incoming sewage, forcing foul-smelling air out the vent. Whether treated or untreated, the raw sewage generates odors that are unpleasant to the vessel""s occupants, and to the occupants of nearby vessels or RVs. Present odor-reducing methods consist of filters that must be maintained or chemical additives that must be monitored, both of which require a measure of undesirable regular maintenance.
Therefore, there exists a need in the art for a method and device to reduce or minimize the generation and perception of odors from marine vessel waste holding tanks without the need for filters or chemical additives.
The present invention is directed toward a method and device for reducing or eliminating the odors emitted from a marine or RV waste holding tank.
In accordance with the present invention, a marine vessel or RV includes a waste holding tank, an aeration pump, an aeration tube, and a macerator/discharge pump. The waste holding tank is installed within the marine vessel or RV and has the aeration tube disposed in the tank, as close to the tank bottom as possible. The output of the aeration pump and aeration tube is in fluid communication with the waste in the holding tank, and is adapted for continuous operation such that air is continuously communicated to the aeration tube.
In further accordance with the present invention, because the waste holding tank is designed to intentionally retain a volume of sewage therein (regardless of the type and design of the discharge pump employed to evacuate the holding tank), the aeration tube is continuously submerged in sewage. The aeration tube continuously injects air into the sewage to create an oxygen-enriched environment in the sewage that assists in reducing the odors emanating from the sewage within the holding tank.
In further accordance with the present invention, the waste holding tank also includes an inlet for sewage, an outlet through which sewage is pumped-out of the holding tank, and a vent. The vent is continuously opened, under the influence of air from the aeration pump injected into the tank via the aeration tube, to expel air from the tank.
In further accordance with the present invention, a method for reducing perceived odors emanating from a marine vessel or RV waste holding tank is provided. The method includes the steps of:
a. submerging an aeration tube in sewage substantially continuously;
b. supplying pressurized air to the aeration tube substantially continuously to thereby inject air into the sewage surrounding the aeration tube and to create an oxygen-enriched condition in the sewage; and,
c. opening the vent under the influence of the pressurized air to gradually and continuously expel air from the holding tank.